The present invention generally relates to a method of manufacturing a semiconductor device and, more particularly, to a method of manufacturing a semiconductor bio-sensor.
With the growth of semiconductor industry and the progress in semiconductor process, computing, communication and consumer devices have been increasingly designed with a compact size. As well, bio-sensors are manufactured in shrinking scales that may therefore fulfill the requirements of portability and compactness. FIGS. 1A to 1C are schematic cross-sectional views illustrating a method of manufacturing a semiconductor bio-sensor in prior art. Referring to FIG. 1A, a substrate 10 may be provided. A first dielectric layer 11 which may include, for example, silicon dioxide (SiO2), may then be formed on the substrate 10. The first dielectric layer 11 may serve as a pad layer.
Referring to FIG. 1B, next, a patterned conductive layer 12 which may include, for example, poly-silicon, may be formed on the first dielectric layer 11. The patterned conductive layer 12 may serve as a sensing resistor for the bio-sensor 1. A portion 12-1 of the patterned conductive layer 12 may be lightly implanted or doped with a first-type impurity, for example, an n-type impurity, which may provide the required resistance for the sensing resistor. Furthermore, second portions 12-2 of the patterned conductive layer 12 may be heavily implanted or doped with the first-type impurity to form electrical contact regions for the sensing-resistor.
Referring to FIG. 1C, a second dielectric layer 14 which may include, for example, SiO2, may then be formed on the patterned conductive layer 12 and the first dielectric layer 11. The second dielectric layer 14 may serve as an insulator for the sensing-resistor of the bio-sensor 1.
With an increasing demand of integrating bio-sensors with other semiconductor devices, it is required to fabricate the bio-sensors and semiconductor devices in a complementary metal-oxide-semiconductor (CMOS) process. However, unfortunately, the thin insulator layer 14 and conductor layer 12 of the bio-sensor, if not properly protected, may be easily damaged in the CMOS process. It may therefore be desirable to have a method that is able to manufacture a semiconductor bio-sensor with other semiconductor devices in a CMOS process.